Joe I have never heard of one being available, I am guessing you mean similar to the Modern Aero Plus 8 style Perspex screen ?
Morgan Park make a very smart adaptation utilising Brooklands screens which is well worth considering, it would appear to offer a similar amount of weather protection as a Speedster screen with the advantage that you can revert to the full screen at any time you chose unlike a Speedster.
http://www.morganpark.de/rennscheiben-system/
